University of Bern: Three Bernese researchers receive Pfizer Prize

Three immunologists from the University of Bern and Inselspital, University Hospital Bern, have been awarded a Pfizer Research Prize for their work. The researchers have shown how our gut microbes influence the formation of antibodies.

The Pfizer Research Prize is one of the most important research prizes for medicine in Switzerland. It is awarded annually to outstanding young scientists who have made distinguished and pioneering contributions to laboratory or clinical research at Swiss research institutes or hospitals. The Pfizer Research Prize is awarded at the request of independent scientific committees in five fields, and the prizes are each worth 15,000 Swiss francs.

Prof. Dr. Stephanie Ganal-Vonarburg, Dr. Hai Li and Dr. Julien Limenitakis, from the Department for BioMedical Research (DBMR) of the University of Bern and Department for Visceral Surgery and Medicine, Gastroenterology at the Inselspital, are awarded for their joint work. In collaboration with Prof. Andrew Macpherson, they have discovered that gut microbes can shape our antibodies.
Prof. Claudio Bassetti, M.D., Dean of the Medical Faculty of the University of Bern: “I am very pleased about this success. The Pfizer Research Prizes are an important recognition – also for the strong commitment of our faculty to the promotion of young researchers.”

Intestinal microbes stimulate white blood cells to produce antibodies
In recent years, new insights have been gained into the influence that benign microbes have on our immune system. These microbes colonize the intestinal mucosa, among other places. However, it was largely unclear which influence these beneficial and harmless microorganisms have to B cells. B cells are white blood cells and a crucial component of our immune system. They recognize foreign structures in the body and produce specific antibodies.

Hai Li, Julien Limenitakis and Stephanie Ganal-Vonarburg wanted to know how, when and where the intestinal microbes on mucous membranes influence B cells in the body. In doing so, the three faced the challenge that both gut bacteria and B cells each form highly complex and highly individual systems. The researchers colonized germ-free mice with various innocuous bacterial strains and then sequenced the DNA of the B cells and their antibodies. Results showed that the bacteria have a clear influence on these immune cells and literally shape their composition. Depending on which bacteria were used and to what extent, the repertoire of B cells in the mice changed, as did their antibody response.

“Our work underscores how important a healthy bacterial flora is for the host organism. Depending on the B-cell population that builds up in an early phase of life through contact with commensal microorganisms, the immune system will react differently to inflammation or pathogens later on,” says Stephanie Ganal-Vonarburg.

The three Bernese researchers’ results show in detail how benign bacteria shape “their” repertoire of B-cells in the analyzed mice. Since the relevant part of bacterial colonization occurs early in life, it is possible that the development of the B-cell repertoire during this critical period also influences the subsequent immune responses during infections and vaccinations.